Digital image displays, such as Liquid Cristal Displays (LCDs), exhibit a sample-and-hold characteristic that may cause blurring of displayed images. For example, in an LCD monitor, a pixel may be assigned to a particular light value. Unlike in a Cathode Ray Tube (CRT) display, the LCD pixel will remain at the same light value until it is reassigned by the display driver. Since digital video and film only include samples or snapshots of images, there may be a significant difference in the location of a fast-moving object between samples. In such cases, the eye will attempt to smooth the movement of the object, but blurring may occur because of the difference between the actual position of the image on the display and the perceived location on the display as a result of eye tracking.
Motion-compensated (MC) Picture Rate Conversion (PRC) techniques are conventionally used to reduce the motion blur on LCD panels and other image display devices. In essence, incoming 60 Hz video is converted to 120 Hertz (Hz) using MC PRC techniques. The increased frequency reduces the hold time on the panel by a factor of two and, therefore, reduces the motion blur. In general, such algorithms are rather demanding on system resources, such as Central Processing Unit (CPU) cycles, memory bandwidth, etc. System resource usage is of particular concern where vertical motion occurs within a scene. Since the processing resources of video display architecture are limited, these limits can be reached during MC PRC in scenes that include fast vertical motion, or other instances of resource-intensive processing. Conventional fallback procedures are typically implemented to reduce the system requirements, but balancing picture quality and resources utilization is difficult.
Typical fall back strategies mainly clip the motion vector to prevent overloading the system. Unfortunately, the clipped motion vector often produces strong artifacts within the corresponding scene. Alternatively, other conventional fall-back strategies (e.g. a non-MC interpolation technique) re-introduce the motion judder for film material. Thus, conventional fall-back strategies either introduce or re-introduce annoying artifacts in the case of video or judder in the case of film material.